As others have said it really depends on the wash, but in general washing them and drying them will fade, shrink, and damage the denim.
This is fine for some pairs, if it's something you want them to fade and get a natural time worn look it's fine. But if you want to keep something dark, or not have holes expand, or lose "dirty" details keep the washing to a minimum.

Most
Kajo 88z
Safado 8aa
Safado 8dk
Lemmen 86t
Sometimes:
Safado 8bi
Lemmen 82m
Can't remember the last time I wore one of my other pairs . . . I should probably do some selling, oh and my Kajo 71j will get busted out once the warmer weather hits.

Long story short, with the larger manufacturers Diesel etc, you can't. They only speak with established stores. Many business are like this. Your best bet is to make contacts in a nearby city through and established store and hope for the best